mirror of
https://github.com/merbanan/rtl_433.git
synced 2026-04-23 02:57:07 -04:00
9232c8dbc1
May still need some tweaking - but works for Danfoss. E3CK has very small pulses! (~12) and should probably have higher samplerate.
98 lines
4.5 KiB
C
98 lines
4.5 KiB
C
/**
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* Pulse demodulation functions
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*
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* Binary demodulators (PWM/PPM/Manchester/...) using a pulse data structure as input
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*
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* Copyright (C) 2015 Tommy Vestermark
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*/
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#ifndef INCLUDE_PULSE_DEMOD_H_
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#define INCLUDE_PULSE_DEMOD_H_
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#include <stdint.h>
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#include "pulse_detect.h"
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#include "rtl_433.h"
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/// Demodulate a Pulse Code Modulation signal
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///
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/// Demodulate a Pulse Code Modulation (PPM) signal where bit width
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/// is fixed and each bit starts with a pulse or not. It may be either
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/// Return-to-Zero (RZ) encoding, where pulses are shorter than bit width
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/// or Non-Return-to-Zero (NRZ) encoding, where pulses are equal to bit width
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/// The presence of a pulse is:
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/// - Presence of a pulse equals 1
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/// - Absence of a pulse equals 0
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/// @param device->short_limit: Nominal width of pulse [samples]
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/// @param device->long_limit: Nominal width of bit period [samples]
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/// @param device->reset_limit: Maximum gap size before End Of Message [samples].
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/// @return number of events processed
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int pulse_demod_pcm(const pulse_data_t *pulses, struct protocol_state *device);
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/// Demodulate a Pulse Position Modulation signal
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///
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/// Demodulate a Pulse Position Modulation (PPM) signal consisting of pulses with variable gap.
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/// Pulse width may be fixed or variable.
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/// Gap between pulses determine the encoding:
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/// - Short gap will add a 0 bit
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/// - Long gap will add a 1 bit
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/// @param device->short_limit: Threshold between short and long gap [samples]
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/// @param device->long_limit: Maximum gap size before new row of bits [samples]
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/// @param device->reset_limit: Maximum gap size before End Of Message [samples].
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/// @return number of events processed
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int pulse_demod_ppm(const pulse_data_t *pulses, struct protocol_state *device);
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/// Demodulate a Pulse Width Modulation signal
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///
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/// Demodulate a Pulse Width Modulation (PWM) signal consisting of short and long high pulses.
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/// Gap between pulses may be of fixed size or variable (e.g. fixed period)
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/// - Short pulse will add a 1 bit
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/// - Long pulse will add a 0 bit
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/// @param device->short_limit: Threshold between short and long pulse [samples]
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/// @param device->long_limit: Maximum gap size before new row of bits [samples]
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/// @param device->reset_limit: Maximum gap size before End Of Message [samples].
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/// @param device->demod_arg = 0: Do not remove any startbits
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/// @param device->demod_arg = 1: First bit in each message is considered a startbit and not stored in bitbuffer
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/// @return number of events processed
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int pulse_demod_pwm(const pulse_data_t *pulses, struct protocol_state *device);
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/// Demodulate a Pulse Width Modulation signal with three pulse widths
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///
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/// Demodulate a Pulse Width Modulation (PWM) signal consisting of short, middle and long high pulses.
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/// Gap between pulses may be of fixed size or variable (e.g. fixed period)
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/// The sync bit will add a new row to the bitbuffer
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/// @param device->short_limit: Threshold between short and middle pulse [samples]
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/// @param device->long_limit: Threshold between middle and long pulse [samples]
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/// @param device->reset_limit: Maximum gap size before End Of Message [samples].
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/// @param device->demod_arg = 0: Short pulse is sync, middle is 0, long is 1
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/// @param device->demod_arg = 1: Short pulse is 0, middle is sync, long is 1
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/// @param device->demod_arg = 2: Short pulse is 0, middle is 1, long is sync
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/// @return number of events processed
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int pulse_demod_pwm_ternary(const pulse_data_t *pulses, struct protocol_state *device);
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/// Demodulate a Manchester encoded signal with a hardcoded zerobit in front
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///
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/// Demodulate a Manchester encoded signal where first rising edge is counted as a databit
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/// and therefore always will be zero (Most likely a hardcoded Oregon Scientific peculiarity)
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///
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/// Clock is recovered from the data based on pulse width. When time since last bit is more
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/// than 1.5 times the clock half period (short_width) it is declared a data edge where:
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/// - Rising edge means bit = 0
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/// - Falling edge means bit = 1
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/// @param device->short_limit: Nominal width of clock half period [samples]
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/// @param device->long_limit: Not used
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/// @param device->reset_limit: Maximum gap size before End Of Message [samples].
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/// @return number of events processed
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int pulse_demod_manchester_zerobit(const pulse_data_t *pulses, struct protocol_state *device);
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#endif /* INCLUDE_PULSE_DEMOD_H_ */
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